You're over thinking this....suffering from analysis paralysis. Just get a 4x5 wood field add a lens and all the other bits that you need and try it. I'd suggest something like the Shen Hao TZ45 or PTB45 or even their non-folding camera. The Tachiharas are fine but they seem to be way over priced in today's market. It wasn't so long ago that one could be purchased brand new from any of the big camera stores for less than $600.
There are new designs coming out too...for example, google Intrepid camera or, check out this guy's kickstarter... Dead Link Removed
Most people who do 4x5 and 8x10 will tell you that they see differently with the Large Format camera, focal length equivalents do not really translate well from the theoretical to the reality.
So, yeah, get a camera and lens, any one, a ShenHao, a Tachihara, a Zone VI, even a Crown Graphic and the stock 135mm will do. Learn the process and accumulate the necessary peripherals and keep looking.